How do i work out the mass of a flywheel. I am given the density as 7500kg/m3, a 500mm diameter and a 10cm thickness.

Please help

2 answers

Switch to the same units, metres.
- good thing we are in metric

diameter = 500 mm = 50 cm = .5 m
so radius = .25 m
height = 10 cm = .1 m

volume of flywheel = π r^2 h
= π(.25)^2 (.1) = .00625π m^3

mass = 750(.00625π) kg
= appr 147.26 kg
Many thanks Reiny